Prevalence and risk factors for bovine brucellosis in the state of Alagoas, Brazil

In order to plan the fight against bovine brucellosis in the state of Alagoas, Brazil, a cross-sectional study was carried out between April and October 2018 to estimate the prevalence of infected herds and animals, as well as the risk factors associated with the disease. Through a two-stage sampling design, blood samples were collected from 3,046 bovine females aged ≥ 24 months from 634 herds, in two different regions of the state. A questionnaire was applied at each farm to assess the association of possible risk factors with the disease. All selected animals were screened by the Rose Bengal test followed by retesting of positives by the Complement Fixation test. For the state, the prevalence of infected herds was estimated at 3.2% [2.1; 4.9] and that of seropositive animals at 0.9% [0.5; 1.4], with no statistical difference between regions. The risk factors identified were pasture rent (OR = 3.11 [1.28; 7.37]) and herd size equal to or greater than 14 females aged ≥ 24 months (OR=4.91 [2.02; 11.66]). It was recommended that the state of Alagoas develop health education action with the beef and dairy cattle production chains, so that producers avoid renting pastures or start practicing it with sanitary care for brucellosis and that they also observe these same concerns when introducing animals in their herds. In addition, the state should consider the convenience of structuring a surveillance system aiming at the eradication of bovine brucellosis, given the low prevalence of infected herds and seropositve animals.